Separated pocket spring mattress

ABSTRACT

A spring mattress comprising a plurality of interconnected coil springs ( 1 ) enclosed in covers ( 2 ), known as a pocket-spring mattress, is described, wherein at least two springs that are located adjacent to one another are spaced apart by an interjacent separation distance (SA), said separation distance exceeding approximately 10% of the diameter of the largest one of the spiral turns of the adjacent springs. Also described is a method of manufacturing a corresponding mattress.

This application is the national phase under 35 U.S.C. §371 of PCTInternational Application No. PCT/SE01/02587 which has an Internationalfiling date of Nov. 23, 2001, which designated the United States ofAmerica.

TECHNICAL FIELD OF INVENTION

The present invention relates to a spring mattress of the kind whereinthe springs are enclosed in covers, known as a pocket-spring mattress,and to method of manufacturing a mattress of this kind.

BACKGROUND OF THE INVENTION

One common technique of manufacturing spring mattress is the one knownas the pocket technique. According to this technique, the springs areenclosed in pockets, i.e. they are enclosed individually by a covermaterial. Owing to this arrangement, the springs become relativelyresilient individually, such that each spring may flex separatelywithout affecting adjacent springs, which increases the user's comfort,since the load will be distributed more evenly across the surface thatreceives the load.

One problem inherent in this type of mattresses is, however that theyare a great deal more expensive to manufacture than many other types ofspring mattresses.

Consequently, there is a need for a mattress that is easier and/orcheaper to manufacture while at the same time offering comfort at leastequivalent to that found in prior-art pocket-spring mattresses.

OBJECT OF THE INVENTION

One of the objects of the present invention therefore is to provide aspring mattress of the kind defined in the introduction, and a method ofmanufacturing said mattress, by means of which the disadvantagesreferred to above are completely or at least partly removed.

This object is achieved in a spring mattress and by means of a method ofmanufacturing said mattress in the manner defined in the appendedclaims.

SUMMARY OF THE INVENTION

The invention relates to a spring mattress comprising a plurality ofinterconnected coil springs enclosed in covers, at least two springslocated adjacent to one another being spaced apart by an interjacentseparation distance, said separation distance exceeding approximately10% of the diameter of the largest one of the spiral turns of theadjacent springs.

In this manner, a spring mattress is obtained which at least in someplaces exhibits separation distances between the springs, making themattress less compact. Consequently, fewer springs are required, theoperational step of enclosing the springs in covers becomes easier andso on. The mattress thus becomes both easier and less expensive tomanufacture. Surprisingly enough it has been found, however that theproperties of the mattress are not noticeably affected from being lesscompact but that essentially the same qualities of comfort are achievedin the inventive mattress as in conventional pocket-spring mattresses.In fact, it has even been found that in some cases the increaseddistance between the springs adds to the individual resilience of thespring, which increases comfort, since each individual spring is able tosupport loads comparatively independently.

In prior-art pocket-spring mattresses the springs may be spaced apart bya certain separation distance but normally this distance amounts to afew millimeters only, sufficient to accommodate a thin weld seam. Inaddition, in prior-art mattress structures the number of springs may bereduced by using larger springs. In practical terms, this solution is,however unsuitable as doing so substantially affects the properties ofthe mattress.

It is particularly preferable that the separation distance is largerthan 15% of the largest one of the spiral turns of the springs that arelocated next to one another, and preferably larger than 20%. Inaddition, it is preferable that the separation distance is larger than 1cm. In this manner a less compact mattress is obtained, which makes thelatter even less expensive and more simple to manufacture.

It is likewise preferable that the covers enclosing adjacent springs arespaced apart by an intermediate separation distance (SB) that exceeds10% of the diameter of the largest one of the spiral turns of theadjacent springs, and preferably exceeds 15% and most preferably exceeds20%.

In this manner, much of the separation distance will consist of materiallocated externally of the enclosing cover parts, which does notnegatively affect the enclosure-dependant stability offered the springs.

A particularly preferred feature is to form the mattress with aplurality of springs that are arranged in strips made from the covermaterial, several such strips being joined together. In this manner, theseparation feature is obtained in that at least most, and preferablyessentially all springs arranged in at least one strip are separatedfrom one another. This is achieved in that the separation distance isformed by joining-together the cover material in a lengthwise extendedinterconnection on each side of the springs or by providing twointerconnection lines for joining-together the cover material on eachside of the springs, said lines being spaced apart in the longitudinaldirection of the strips.

This makes it easy to achieve the separation feature without having tosupply additional separation material.

It is particularly preferred that mattresses in accordance with theinvention have a spring density in at least one lengthwise direction, inwhich separation distances are provided, of less than 15 springs permeter, and preferably less than 13 springs per meter. The resultingmattress is a great deal more simple and less expensive thanconventional mattresses, which as a rule have 30 springs and more in thelengthwise direction of the mattress.

The invention likewise concerns a method of manufacturing a mattress ofthe kind defined above. The method comprises the steps of enclosing thesprings in a cover material; and interconnecting the springs with oneanother, whereby at least two springs that are located adjacent to oneanother are interconnected in such a manner that an interjacentseparation distance is formed between the springs, said separationdistance exceeding about 10% of the diameter of the largest one of thespiral turns of springs located adjacent to one another.

BRIEF DESCRIPTION OF THE DRAWINGS

In the annexed drawings:

FIG. 1 shows a spring mattress designed in conformity with theinvention;

FIG. 2 shows a strip comprising separated springs in accordance with afirst embodiment to be used in a mattress in accordance with theinvention; and

FIG. 3 shows a strip comprising separated springs in accordance with asecond embodiment to be used in a mattress in accordance with theinvention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The invention will be described in the following for exemplifyingpurposes by way of one embodiment and with reference to the accompanyingdrawings.

A spring mattress in accordance with the invention comprises a pluralityof interconnected coil springs 1, which are enclosed in covers 2.Suitably, the cover is made from a preferably weldable textile fabricbut other materials, such as various types of plastic material couldequally well be used. It is likewise possible to use non-weldabletextile fabrics, such as cotton fabrics. Normally, strips 3 ofinterconnected, cover-enclosed pocket springs are manufacturedautomatically, whereupon the strips are cut into suitable lengths andjoined together side by side to form mattresses.

Preferably, the covers are dimensioned to ensure that the maximumenclosed height amounts to at least 3 cm and preferably to at least 5cm.

Coil springs of many different sizes could be used in conjunction withthe present invention, and in principle any desired spring size, largeor small, may be used. Preferably, however springs are used having adiameter of 2–10 cm, and most preferably a diameter of 6 cm. Preferablythe springs comprises at least four spiral turns and preferably fewerthan 10 spiral turns. In addition, it is an advantage to manufacture thesprings from helically coiled wires having a thickness in the rangebetween 0.5 and 3.00 mm and preferably a wire thickness in the range of1.5 to 2.2 mm.

In the spring mattress in accordance with the invention at least atleast two adjacent springs are spaced apart by an interjacent separationdistance SA, said separation distance exceeding 10% of the diameter ofthe largest one of the spiral turns of the adjacent springs, andpreferably it exceeds 15% of the diameter of the largest one of thespiral turns of adjacent springs, and preferably exceeds 20%. Inaddition, the separation distance preferably exceeds 1 cm. Preferablyalso the covers enclosing adjacent springs are spaced apart by anintermediate separation distance SB, said separation distance exceeding10% of the diameter of the largest one of the spiral turns of theadjacent springs, and preferably exceeding 15% and most preferablyexceeding 20%. In addition, the separation distance SB preferably alsois larger than 1 cm.

These separation distances preferably are arranged between essentiallyall springs in the lengthwise direction of the mattress. This may beachieved by arranging two joining-together lines 4 that are spaced apartin the lengthwise direction of the strips as illustrated in FIG. 2, soas to join-together the cover material on each side of the springs.Alternatively, it is instead possible to provide one or severalinterconnection means 5 to join-together the cover material in aninterconnection extended in the lengthwise direction of the strips oneach side of the springs, which interconnection means could be e.g. awide weld seam, as illustrated in FIG. 3. Likewise, it is possible touse continuous welding lines instead of spot-welded seams, as shown inFIGS. 2 and 3, Other types of interconnections are possible too, such asone or several stitched seams.

The springs could, however also be separated in other ways, such as byintroducing separation members or the like between the strips.

The invention makes it possible to use less than 30 springs andpreferably about 25 springs and most preferably about 22 springs inmattresses having a length in excess of 180 cm. It is also preferablethat in the mattresses in accordance with the invention the density ofsprings in the lengthwise direction or directions, in which theseparation distances are provided, is less than 15 springs per meter andpreferably is less than 13 springs per meter.

In the manufacture of mattresses in accordance with the invention, thesprings are enclosed in a cover material. Thereafter, or in conjunctionwith the enclosing step, the springs are interconnected with one anotherto form mattresses. In this operation, care is taken to ensure that atleast two springs located adjacent to one another are interconnected insuch a manner that an interjacent spring-separation distance is formedbetween the springs the length of which exceeds 10% of the diameter ofthe largest one of the spiral turns of the adjacent springs.

It is particularly advantageous to interconnect the springs by arranginga plurality of springs in strips formed by the cover material and tojoin-together several strips of this kind. The separation of the springsmay be effected by joining-together the cover material in a lengthwiseextended interconnection of the strips on each side of the springs, orby arranging two interconnection lines for joining-together the covermaterial on each side of the springs, which are separated in thelengthwise direction of the strips.

As already mentioned the covers comprising springs preferably arearranged in successive rows, whereupon such rows are attached to oneanother side by side as indicated in FIG. 1. Preferably, the rows areattached to one another in 2–3 vertically spaced attachment pointsopposite the associated spring. A larger or smaller number of attachmentpoints could of course also be used. It is likewise possible to use onelong attachment line extending essentially in parallel with thelongitudinal direction of the springs instead of several, shorterattachment points. It is likewise possible to join-together the stripsby means of a string of glue or the like extending in the direction ofextension of the strips. The joining-together of rows side by side insuccession could be effected by welding or gluing, as mentionedpreviously. Other alternative joining-together means could be used, suchas clamps, Velcro tapes or some other suitable joining-together methodbe used. It is likewise possible to attach the rows to one another byusing interconnecting sheets at the upper and lower faces of thesprings. The sheets could be made from a textile material and beattached by means of gluing or welding.

By joining-together the strips in this way opposite the springs in therespective strip the separation distances will be positioned inalignment with one another. This position is the preferred one, althoughit is likewise possible to arrange the strips in such a manner that thesprings will be staggered, i.e. positioned offset relative to oneanother. In the latter case the springs as a whole may be arranged moredensely across the mattress than is the case in conventionalpocket-spring mattresses, although as a rule this is not desirable.

It is also possible to use differently-sized separation distances indifferent zones or areas of the mattress and to use e.g. largerseparation distances in areas that in normal use of the mattress areless exposed to load, and smaller separation distances in areas exposedto more heavy loads.

The mattress in accordance with the invention offers resilienceproperties equivalent to those achieved in conventional pocket-springmattresses, providing the same firmness, comfort and so on. Possiblysomewhat harder springs than normal may be used to increase the mattressfirmness.

The invention has been described above with reference to one embodiment.Several varieties of the invention are possible, however. For example,other cover materials may be used as also differently-sized springs, andso on. Such close varieties should be considered to be within the scopeof protection of the invention as defined in the appended claims.

1. A spring mattress comprising a plurality of interconnected coilsprings enclosed in covers, at least two springs that are locatedadjacent to one another being spaced apart by an interjacent separationdistance (SA), said separation distance exceeding approximately 10% ofthe diameter of the largest one of the spiral turns of the adjacentsprings, the covers enclosing adjacent springs being spaced apart by aninterjacent separation distance (SB), said separation distance exceeding15% of the diameter of the largest one of the spiral turns of theadjacent springs, the springs having helically coiled wires with athickness in the range of between 0.5 and 3.0 mm, the spiral turn of thesprings having the largest diameter having a diameter size of 2–10 cm,the density of springs in at least one lengthwise direction, in whichseparation distances are provided, being less than 15 springs per meter.2. The spring mattress as claimed in claim 1, wherein said separationdistance (SA) exceeds 15% of the diameter of the largest one of thespiral turns of the adjacent springs.
 3. The spring mattress as claimedin claim 1 or 2, wherein the separation distance (SA) exceeds 1 cm.
 4. Aspring mattress as claimed in claim 1, wherein the an interjacentseparation distance (SB) exceeds 20% of the diameter of the largest oneof the spiral turns of the adjacent springs.
 5. The spring mattress asclaimed in claim 1, wherein the mattress comprises a plurality ofsprings arranged in strips of the cover material, several strips of thiskind being joined together.
 6. The spring mattress as claimed in claim5, wherein at least most springs in at least one strip are separatedfrom one another.
 7. The spring mattress as claimed in claim 6, whereinthe springs in a majority of the strips are separated from one another.8. The spring mattress as claimed in any one of claims 5–7, wherein theseparation distance (SB) is achieved by joining-together the covermaterial in a joint extended in the lengthwise direction of the stripson each side of the springs.
 9. The spring mattress as claimed in anyone of claims 5–7, wherein the separation distance (SB) is achieved bytwo interconnection lines for joining-together the cover material oneach side of the springs, said lines being spaced apart in thelengthwise direction of the strips.
 10. The spring mattress as claimedin claim 5, wherein the strips are arranged in parallel with thelengthwise direction of the mattress.
 11. The spring mattress as claimedin claim 1, wherein the springs comprise at least four spiral turns. 12.The spring matter as claimed in claim 1, wherein the cover is made froma weldable textile fabric, the joining-together being effected bywelding.
 13. The spring mattress as claimed in claim 1, wherein saidseparation distance (SA) exceeds 20% of the diameter of the largest oneof the spiral turns of the adjacent springs.
 14. The spring mattress asclaimed in claim 1, wherein the spiral turn of the springs having thelargest diameter has a diameter size of 6 cm.
 15. The spring mattress asclaimed in claim 1, wherein the springs comprise fewer than 10 spiralturns.
 16. The spring mattress as claimed in claim 1, wherein thehelically wiled wires of the springs have a thickness in the range ofbetween 1.5 and 2.2 mm.
 17. A spring mattress comprising a plurality ofinterconnected coil springs enclosed in covers, wherein at least twosprings that are located adjacent to one another are spaced apart by aninterjacent separation distance (SA), said separation distance exceedingapproximately 10% of the diameter of the largest one of the spiral turnsof the adjacent springs and the density of springs in at least onelengthwise direction, in which separation distances are provided, beingless than 15 springs per meter, the springs having helically coiledwires with a thickness in the range of between 0.5 and 3.0 mm,the spiralturn of the springs having the largest diameter having a diameter sizeof 2–10 cm.
 18. The spring mattress as claimed in claim 17, wherein thedensity of spring in the at least one lengthwise direction, in whichseparation distances are provided, is less than 13 springs per meter.19. The spring mattress as claimed in claim 17, wherein the springscomprise at least four spiral turns.
 20. The spring mattress as claimedin claim 17, wherein the cover is made from a weldable textile fabric,the joining-together being effected by welding.
 21. A method ofmanufacturing a spring mattress of the kind comprising a plurality ofinterconnected coil springs, which are enclosed in covers, comprisingthe steps of: enclosing the springs in a cover material; andinterconnecting the springs with one another by interconnecting at leasttwo springs located adjacent to one another in such a manner That aninterjacent separation distance (SA) is formed between the springs, saidseparation distance (SA) exceeding about 10% of the diameter of thelargest one of the spiral turns of springs located adjacent to oneanother, the covers enclosing adjacent springs being spaced apart by aninterjacent separation distance (SB), said separation distance exceeding15% of the diameter of the largest one of the spiral turns of theadjacent springs, the springs having helically coiled wires with athickness in the range of between 0.5 and 3.0 mm, the spiral turn of thesprings having the largest diameter having a diameter size of 2–10 cm,the density of springs in at least one lengthwise direction, in whichseparation distances are provided, being less than 15 springs per meter.22. The method as claimed in claim 21, wherein the separation distanceexceeds 15% of the diameter of the largest one of the spiral turns ofsprings located adjacent to one another.
 23. The method as claimed inclaim 21 or 22, wherein said separation distance is larger than 1 cm.24. The method as claimed in claim 21, wherein the step ofinterconnecting the springs comprises arranging a plurality of springsin strips made by the cover material, several such strips being joinedtogether.
 25. The method as claimed in claim 24, wherein separating thesprings is achieved by joining-together the cover material with a jointwith an extension in the lengthwise direction of the strips on each sideof the springs.
 26. The method as claimed in claim 24, wherein theseparation distance is achieved by two interconnection lines forjoining-together the cover material on each side of the springs, saidlines being spaced apart in the lengthwise direction of the strips. 27.The method as claimed in any one of claims 25–26, wherein the cover ismade from a weldable textile material, said joining-together beingeffected by welding.
 28. The method as claimed in claim 21, wherein theseparation distance exceeds 20% of the diameter of the largest one ofthe spiral turns of springs located adjacent to one another.
 29. Thespring mattress as claimed in claim 21, wherein the step ofinterconnecting the springs comprises arranging a plurality of springsin strips made by the cover material, several such strips being joinedtogether.
 30. A method of manufacturing a spring mattress of the kindcomprising a plurality of interconnected coil springs, which areenclosed in covers, comprising the steps of: enclosing the springs in acover material; and interconnecting the springs with one another byinterconnecting at least two springs located adjacent to one another insuch a manner that an interjacent separation distance (SA) is formedbetween the springs, said separation distance (SA) exceeding about 10%of the diameter of the largest one of the spiral turns of springslocated adjacent to one another, the density of springs in at least onelengthwise direction, in which separation distances are provided is lessthan 15 springs per meter, the springs having helically coiled wireswith a thickness in the range of between 0.5 and 3.0 mm, the spiral turnof the springs having the largest diameter having a diameter size of2–10 cm.
 31. The spring mattress as claimed in claim 30, wherein thedensity of springs in that at least one lengthwise direction, in whichseparation distances are provided, is less than 13 springs per meter.32. The spring mattress as claimed in claim 30, wherein the separationdistance exceeds 15% of the diameter of the largest one of the spiralturns of springs located adjacent to one another.
 33. The springmattress as claimed in claim 30, wherein the separation distance exceeds20% of the diameter of the largest one of the spiral turns of springslocated adjacent to one another.
 34. The spring mattress as claimed inclaim 30, wherein said separation distance is larger than 1 cm.
 35. Thespring mattress as claimed in claim 30, wherein the step ofinterconnecting the springs comprises arranging a plurality of springsin strips made by the cover material, several such strips being joinedtogether.
 36. The spring mattress as claimed in claim 35, whereinseparating the springs is achieved by joining-together the covermaterial with a joint with an extension in the lengthwise direction ofthe strips on each side of the springs.
 37. The spring mattress asclaimed in claim 35, wherein the separation distance is achieved by twointerconnection lines for joining-together the cover material on eachside of the springs, said lines being spaced apart in the lengthwisedirection of the strips.
 38. The spring mattress as claimed in claim 35,wherein the cover is made from a weldable textile material, saidjoining-together being effected by welding.